arm64: Add workaround for Cavium Thunder erratum 30115

Some Cavium Thunder CPUs suffer a problem where a KVM guest may
inadvertently cause the host kernel to quit receiving interrupts.

Use the Group-0/1 trapping in order to deal with it.

[maz]: Adapted patch to the Group-0/1 trapping, reworked commit log

Tested-by: Alexander Graf <agraf@suse.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@linaro.org>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3dcd7ec..6252365 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -480,6 +480,17 @@
 
 	  If unsure, say Y.
 
+config CAVIUM_ERRATUM_30115
+	bool "Cavium erratum 30115: Guest may disable interrupts in host"
+	default y
+	help
+	  On ThunderX T88 pass 1.x through 2.2, T81 pass 1.0 through
+	  1.2, and T83 Pass 1.0, KVM guest execution may disable
+	  interrupts in host. Trapping both GICv3 group-0 and group-1
+	  accesses sidesteps the issue.
+
+	  If unsure, say Y.
+
 config QCOM_FALKOR_ERRATUM_1003
 	bool "Falkor E1003: Incorrect translation due to ASID change"
 	default y
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index b3aab8a..8d2272c 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -38,7 +38,8 @@
 #define ARM64_WORKAROUND_REPEAT_TLBI		17
 #define ARM64_WORKAROUND_QCOM_FALKOR_E1003	18
 #define ARM64_WORKAROUND_858921			19
+#define ARM64_WORKAROUND_CAVIUM_30115		20
 
-#define ARM64_NCAPS				20
+#define ARM64_NCAPS				21
 
 #endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 2ed2a76..0e27f86 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -133,6 +133,27 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 		MIDR_RANGE(MIDR_THUNDERX_81XX, 0x00, 0x00),
 	},
 #endif
+#ifdef CONFIG_CAVIUM_ERRATUM_30115
+	{
+	/* Cavium ThunderX, T88 pass 1.x - 2.2 */
+		.desc = "Cavium erratum 30115",
+		.capability = ARM64_WORKAROUND_CAVIUM_30115,
+		MIDR_RANGE(MIDR_THUNDERX, 0x00,
+			   (1 << MIDR_VARIANT_SHIFT) | 2),
+	},
+	{
+	/* Cavium ThunderX, T81 pass 1.0 - 1.2 */
+		.desc = "Cavium erratum 30115",
+		.capability = ARM64_WORKAROUND_CAVIUM_30115,
+		MIDR_RANGE(MIDR_THUNDERX_81XX, 0x00, 0x02),
+	},
+	{
+	/* Cavium ThunderX, T83 pass 1.0 */
+		.desc = "Cavium erratum 30115",
+		.capability = ARM64_WORKAROUND_CAVIUM_30115,
+		MIDR_RANGE(MIDR_THUNDERX_83XX, 0x00, 0x00),
+	},
+#endif
 	{
 		.desc = "Mismatched cache line size",
 		.capability = ARM64_MISMATCHED_CACHE_LINE_SIZE,